The invention relates to a traveling water screen for filtering the water flowing through a channel. More particularly, the invention relates to an apparatus for regulating the differential water pressure across the traveling water screen.
Power plants, foundries, and other types of industrial facilities are often located near a body of water in order to satisfy their need for water, which is typically used as a coolant. However, water taken from a natural source must be filtered to prevent debris from being taken in with the water.
Typically, traveling water screen filtration units are used to accomplish the desired filtering. A series of channels are positioned in a body of water to direct the flow of water through the channels into the intake ports of the facility. The traveling water screens are mounted in the channel to filter the water flowing through the channel.
A common configuration for a traveling water screen provides a frame having an upstream portion or face, a downstream portion, and opposite side portions connected between the upstream portion and the downstream portion. The frame is centrally positioned in the channel and supports along the side portions first and second vertically extending water screens. Water is directed into the channel around the upstream face of the traveling water screen frame and through the water screens.
It is known in the art to provide a pair of baffles for directing the water flow through the water screens. The baffles are typically connected between the downstream portion of the traveling water screen frame and the channel sidewalls. One such arrangement is shown in U.S. Pat. No. 4,935,131.
It is also known in the art to provide a blow-out panel in the traveling water screen. In the known construction, an opening is provided in the baffle and a removable panel is mounted on the baffle to seal the opening. When the differential pressure across the traveling water screen exceeds a limit beyond which damage to the traveling water screen could result, the water pressure causes the panel is to be permanently blown-off of the baffle to allow water to flow through the opening thereby reducing the differential pressure.
When the differential pressure, and accordingly, the risk of damage to the water screen, has been reduced, a new blow-out panel must be installed to reseal the opening. Installation of the new blow-out panel requires a significant amount of time and effort during which the traveling water screen is not operable.